The invention relates to polymer compositions, sol or gel compositions, electrically conductive compositions containing a latex polymer, and the preparations thereof.
The achievement of tailored electrical properties of compositions containing polymers is usually pursued in several ways. One approach consists of modifying the intrinsic bulk properties of polymers by processing, especially by pyrolysis. In this approach, acceptable electrical properties are developed by altering the chemical composition or structure of the initial material. A second approach is to attain the desired conductivity by incorporating macroscopic pieces of conducting material (metal flakes, carbon-black particulates, or carbon fibers, for example) in host polymers to form conducting composites. It is the traditional approach in the preparation of conducting polymers and is used today in the fabrication of nearly all commercial products based on conductive polymers. Another approach focuses on increasing the electrical conductance of conjugated polymers (i.e., polymers which already have at least some electrical conductance) at the molecular level by controlled incorporation of molecular dopants that may or may not form charge-transfer complexes with the host conjugated polymer. It is called molecular doping because it consists of diffusing isolated molecular dopants (AsF.sub.5 or I.sub.2, for example) into conjugated polymers.
Polymers capable of being stabilized in aqueous media are called latex polymers and a latex ordinarily contains at least one latex polymer and at least one surfactant dispersed in water. Presently, latex polymers are not conjugated, e.g., latex polymers are considered insulators. In order to produce acceptable electrical conductance properties in compositions containing latex polymers, materials responsible for such conductance must be compatibly combined with the latex. Compositions containing latex polymers coagulate when admixed with aqueous solutions of salts. For instance, an aqueous solution of cupric acetate added to a latex composition containing styrene butadiene rubber will cause coagulation of the styrene butadiene rubber within a short time after contact.
However, investigators have prepared hydrosols which contain materials such as colloidal antimony oxide in an attempt to find materials which may be added compatibly to a latex composition (i.e., added without coagulation). For example, in U.S. Pat. No. 3,960,989 issued to Petrow et al., a colloidal antimony oxide (hydrosol) was mixed in equal amounts with polyvinylidene chloride (PVDC) to improve the clarity of PVDC films.
The search continues for methods to compatibly mix salts with latex polymers. The resultant admixture of latex and salt provides for a number of useful compositions such as electrically conductive compositions containing latex polymers.